The present invention relates to a method of securing a reverse winding on a tube and a device for carrying out this method.
It is already known to grasp the thread extending to a thread-holding device and pull it out to the empty bobbin tube while introducing it into the gripping line of the winding device (DT-OS No. 2.332.327). In the course of this, the thread is gripped between the end of the tube and a member rotating with the tube and a thread reserve is formed from the length of thread between nip point and delivery point. When the finished bobbin is removed from the bobbin holder, there is a risk that the end of the thread reserve, which is not secured to the end of the bobbin, may unwind and tear off. There is also a risk of unwinding and tearing during transport, so that, in some circumstances, no thread reserve is available during the processing for connection to the beginning of a thread of a fresh bobbin.
It is also known to guide the thread between a pneumatic thread-holding device and the tube in the region of the reserve winding which is provided, while the reserve winding is composed of the thread produced by the thread-holding device (DT-OS No. 2.431.145). For this purpose, however, the thread must wrap around the tube, which complicates the changing of the bobbin. Apart from this, the end of the thread of the reserve winding is unsecured, so that the disadvantages outlined above also occur here.
It is also known to provide a thread-catching element at the end of the tube, extending axially beyond the end of the tube (FR-PS No. 2.098.134). This is not in a position to secure the end of the thread, however. It is further known to provide an incision or a notch at the end of the tube (DT-OSen Nos. 2.204,674, 2.330.961 and 2.347.644). The incision or the notch is enlarged with time so that, in the long run, no reliable holding of the end of the thread can be ensured by this means.